fix(desktop): refine focus reclaim logic to not steal from dialogs/routes

- Only reclaim focus when primary focus is truly idle: null, root scope,
  empty FocusScopeNode (no focused children), or a descendant of our scope.
- Add _isEmptyFocusScope() to check if a FocusScopeNode has no focused children.
- Add _isDescendantOfScopeFocus() to distinguish internal idle scopes from
  external scopes (dialogs, routes) that should retain focus.
- Fixes issue where global shortcuts would steal focus from open dialogs/routes.

Author: leduckhc

app/lib/desktop/chat/keymap_scope.dart

@@ -59,17 +59,51 @@ class _DesktopKeymapScopeState extends ConsumerState<DesktopKeymapScope> {
 
   /// Re-grabs focus for [_scopeFocus] when no concrete widget holds it. A real
   /// focusable (text field, button) is a leaf [FocusNode]; when focus instead
-  /// rests on a [FocusScopeNode] (or is null) nothing is truly focused, so we
-  /// pull it back into the scope without stealing from any active widget.
+  /// rests on a [FocusScopeNode] with no focused children (or is null) nothing
+  /// is truly focused, so we pull it back into the scope without stealing from
+  /// any active widget.
+  /// 
+  /// Focus is considered "idle" only when:
+  /// 1. No widget has focus (primaryFocus is null)
+  /// 2. Focus is on the framework root scope (empty focus)
+  /// 3. Focus is on a [FocusScopeNode] that has no focused children (empty scope)
+  /// 4. Focus is on a [FocusScopeNode] that is a descendant of our scope
+  ///    (internal idle scope like an empty [FocusScope] wrapper in our subtree)
+  /// 
+  /// We do NOT reclaim focus when a dialog, settings route, or other overlay
+  /// holds focus, since those create their own focus scopes WITH focused children
+  /// outside our subtree.
   void _reclaimFocusWhenIdle() {
     if (!mounted || !_scopeFocus.canRequestFocus) return;
     final primary = FocusManager.instance.primaryFocus;
-    final idle = primary == null || primary is FocusScopeNode;
-    if (idle && !_scopeFocus.hasPrimaryFocus) {
+    final isIdle = primary == null ||
+        primary == FocusManager.instance.rootScope ||
+        _isEmptyFocusScope(primary) ||
+        _isDescendantOfScopeFocus(primary);
+    if (isIdle && !_scopeFocus.hasPrimaryFocus) {
       _scopeFocus.requestFocus();
     }
   }
 
+  /// Returns true if [node] is a [FocusScopeNode] with no focused children,
+  /// indicating an empty focus scope (idle focus).
+  bool _isEmptyFocusScope(FocusNode node) {
+    if (node is! FocusScopeNode) return false;
+    return node.focusedChild == null;
+  }
+
+  /// Returns true if [node] is [_scopeFocus] or a descendant of it in the
+  /// focus tree. Used to distinguish internal idle scopes from external scopes
+  /// (dialogs, routes) that should not have focus stolen.
+  bool _isDescendantOfScopeFocus(FocusNode node) {
+    FocusNode? current = node;
+    while (current != null) {
+      if (current == _scopeFocus) return true;
+      current = current.parent;
+    }
+    return false;
+  }
+
   @override
   Widget build(BuildContext context) {
     final keymap = ref.watch(keymapProvider);

app/test/desktop/keymap_scope_test.dart

@@ -134,4 +134,4 @@ void main() {
     await pressCtrl(tester, LogicalKeyboardKey.keyP);
     expect(opened, 1);
   });
-}
+}